Fig. 3

Longitudinal SARS-CoV-2 IgG antibody levels (logarithmic titres, BAU/mL) among those initially seropositive in the May/June 2020 or December 2020 timepoints by vaccination status (N = 31) * In Germany: (1) May/June 2020 was following the first wave where the wild-type SARS-CoV-2 was reported as dominant; (2) December 2020 was in the second wave where the wild-type SARS-CoV-2 was reported as dominant; (3) the third wave occurred in Spring 2021 where the wild-type SARS-CoV-2 and Alpha variant were reported as dominant; and (4) January 2022 was following the fourth wave where the Delta variant was reported as dominant and where the spread of the Omicron variant was reported before the fifth wave [17], Abbreviations: IgG - Immunoglobulin G, n – number of Participants